Round containers, having corresponding circular lids or covers, are widely employed in a variety of current packaging applications, such as for commercial baked goods, retail delicatessen foods, and the like. In many instances, such lids are provided with openings, and generally the openings have applied thereover a patch of synthetic film or other translucent material, to provide a window. So long as the opening in the lid is both circular and also concentric, orientation for purposes of applying the window material represents no problem. However, if either the configuration of the opening is non-circular, or the opening (irrespective of its configuration) is asymmetrically disposed in the lid, orientation is a necessary consideration.
More specifically, since a circular member provides no inherent reference point by which its rotational position can be established and maintained, the application of a window film over a non-circular or asymmetrically disposed opening of a circular lid has heretofore necessitated, as a practical matter, the use of a piece of material having an area sufficient to cover the opening in all possible orientations of the lid. This obviously is wasteful of material. Similar difficulties are encountered in the application of glue or printed matter, to a circular lid, in registry with some existing feature thereof.
Accordingly, it is a object of the present invention to provide a novel blank for producing a circular lid or cover, which blank may be employed in a machine without substantial change of angular orientation (rotational position) during passage therethrough.
It is also an object of the invention to provide such a blank, which constitutes a simple and economical modification of conventional blanks used to produce circular lids.
Another object is to provide such a blank, having an opening over which a window film may be applied with a minimum amount of waste of window material.
Still another object is to provide a novel blank of the foregoing type, in which the means for maintaining orientation may be furnished by portions of the lid stock which would normally be discarded as broke.
A further object of the invention is to provide a novel method by which a windowed, circular lid may be produced, economically and with outstanding facility.